青藏高原东侧一次特大暴雨过程的分析

Analyese on A Heavy Rain Process on the East Side of Qinghai-Xizang Plateau

利用常规物理量场和GMS-5卫星云图逐时资料, 对2002年6月8日发生在青藏高原东侧四川盆地的一次MCC型特大暴雨天气过程进行了分析。结果表明: 本次特大暴雨过程产生在宽槽暖湿区内, 是由西南低空急流组织的两个MCC先后影响所致, 具有低空辐合(正涡度)、高空强辐散(负涡度)的动力结构, MCC及特大暴雨的发展和维持与高空急流入口区同低空急流出口区次级环流上升支的叠加有密切联系。

Using the hourlysatellite images and physical quantity field data, the cloud characteristicand physical structure for the heavy rain in Sichuan basin on the east side of Qinghai-Xizang Plateau during 8~9 June, 2002 are analyzed. The results show that the heavy rain was caused by two mesoscale convective storm complexes(MCC) in occurring the environment of warm and wet, and it is found that there is the dynamical structure of upper-level strong divergnce (negative vorticity) and low-level convergence (positive vorticity) in physical field. The development and maintenance of the MCC and heavy rainwere closely related to the superposition by the asending branchs of the direct circulation in the entrance region of upper-level jet and the secondary circulation in the exit region of low-level jet.